My problem started about a week ago. It just started missing and hesitating like crazy when me and my buddy were out repoing a van. We figured plugs and wires so we went the next day and bought some and put them on. My car ran like a dream for the next 3 days then it started do the same thing, sometimes worse than it was doing it before. Sometimes it wont miss at all, like yesterday it went all day with out doing it but sometimes it'll miss all day long and really bad. It usually does it once the car gets warmed up. No one really seems to know what it is that I've talked to. Cap and rotor button are pretty new, if it was the coil it wouldn't run at all. I figure if it was a fuel filter it would do it all the time. I've also noticed that when it misses there is a metal to metal noise. If I can't get the problem solved I'm going and getting me another car asap. I can't drive around like this. Sorry so long, I just hope someone can help.

get your ignition control module tested

one of the plugs may be fauling. that was happening to my friends 72 jeep wagoneer. cept it would miss when it was cold and run fine when it warmed up most of the time anyways.

i had a similar problem, but for me it turned out to be one of my wires was cracked. but i will run through the list of what i did and what were possible suspects....everyone on the board was great for thier help fortunately it was something stupid. but def somethings below that are cheap and easy....will make your car run much smoother....and increase MPG. after i was done trouble shooting my hesitation my mpg went from 130 a tank to 225. it
ended up that my ignition module, o2 sensor and fuel filter were all working, but needed a replacement.

heres the post and a summary to follow: (its a good read and lots of 411)

http://www.thirdgen.org/techbb2/show...threadid=62170

Quick summary of above:
-------------------------------
1) check condition of wires and make sure resistance is consistant with multimeter
2) check condition and GAP of spark plugs (oil/detonation/etc...)
3) fuel filter (very easy and cheap....DO IT ANYWAY, it increased my MPG)
4) test your ignition coil with a multimeter (near AC)....chiltons or haynes tells you how, i can look it up if ya want
5) check fuel pressure to make sure fuel pump is good (38-45 psi i think)
6) 02 sensor....is is new? easy change and pretty cheap
7) cap & rotor......new? condition? don't forget about the the ingnition module inside, mine needed to be changed (GM did it - damn the 'rents)
8) and also check the TPS sensor on the TB with a multimeter
9) i also have heard to change out the CTS as a long shot

My vote goes to a loose plug or two, or an exhaust leak around the manifold area...

My car misses like crazy, and right after/while doing my coil i noticed I was missing at least 3 header bolts... Exhaust leak... missfire. Sometimes it's worst than others. It also creates a tick, sometimes it can get bad...

ALSO! Check and make sure all your accessories are tight! A bolt fell off my PS pump... I don't know how long it had been like that, but after my marbly sounds returned, I got pissed! I thought it was my timing chain, or my brand new water pump...

I went to check all the acc. ... wobbled them all, and when I got to the PS pump... big wobble... WTF? ok I need a new one... looked around back, BAM! No nut holding it on... got a nut, put it on...no noise! It was good.!

Thats not going to create a miss or lsss of power, but in my case it was a combo of things.

Good luck.

Check the timing, too... as the car gets warm, the computer advances timing a bit more... if you're timing's over-advanced to begin with, it might be off the chart when the car gets warm!

Did you keep your old plugs so you could "read" them? Were the gaps still good? Was the color of the insulator around the center electrode a normal "tan-ish" color? Any cracked/destroyed center insulators? My timing was once so far over-advanced, the detonation was so bad that it destroyed the center of the #1 spark plug. I pulled the plug and there was nothing left in the center- that's now my cylinder with the lowest compression.

Everyone hit good points.
Look for plug wires engine bay night time.
You'll see it (problem wire) right way, promise.
IT COULD ALSO BE YOUR FUEL PUMP.
That's what mine was.
No changing fuel filter won't fix that problem.
My pump was a hokey hatchet job by previous ?.
Replaced, my car SINGS now!
But that tank job is a two person project.

If your EGR valve isnt working properly your combustion chamber might be getting too hot and the knock sensor might be retarding the timing . Or the knock sensor itself might be acting up. Just a thought.